1. Field of the Invention
The invention relates to a lighting device, more particularly to a multi-function variable focusing lighting device which can be operated as a flashlight and as a signaling baton.
2. Description of the Related Art
Referring to FIG. 1, a conventional variable focusing flashlight disclosed in U.S. Pat. No. 5,213,408 is shown to comprise a conductive barrel 10 for housing a battery 12 therein, a tail cap 13 mounted on one end of the barrel 10 and provided with a compression spring 131 for urging the battery 12 towards the other end of the barrel 10, a lamp base 11 for mounting a lamp 14 adjacent to the other end of the barrel 10, and a head assembly 17 mounted rotatably on the other end of the barrel 10 and provided with a planar lens 171 and a parabolic reflector 170 with an open tail end to receive the lamp 14. First and second conductors 113, 114 are mounted in the lamp base 11 and are connected electrically and respectively to lamp terminals of the lamp 14. A push member 111 extends through the lamp base 11 and has a first end abutting against the battery 12 and a second end abutting against the open tail end of the reflector 170. The first conductor 113 has one end extending radially along the bottom side of the lamp base 11 within the barrel 10. The second conductor 114 couples electrically the lamp 14 and the barrel 10.
The head assembly 17 is mounted threadedly to the barrel 10 so as to be controllably translatable therealong when rotated with respect to the barrel 10, thereby resulting in a variable focusing effect. Rotation of the head assembly 17 in a direction to result in movement toward the barrel 10 eventually causes the reflector 170 to push the push member 111 and the battery 12 and move the battery 12 away from the first conductor 113, thereby breaking electrical connection between the lamp 14 and the battery 12.
In the aforementioned conventional flashlight, rotation of the head assembly 17 is performed to activate and vary focusing of the flashlight. Since the light output of the conventional flashlight is directed only through the head assembly 17, the flashlight is not ideal for use as a lantern or as a signaling baton.
Referring to FIGS. 2, 3 and 4, a conventional multi-function lighting device disclosed in U.S. Pat. No. 5,412,548 is shown to comprise a head section 18 and an elongate handle 19. The head section 18 includes a slidable coupling 180 which is sleeved on the elongate handle 19 so as to be longitudinally shiftable over the latter, an axially extending elongate sleeve 181 which is secured to and shiftable with the coupling 180 and which is made of a transparent or translucent material so as to permit transmission of light therethrough, and an end cap 182 which is secured to the elongate sleeve 18]and which has a reflector 191 provided therein. A light source 190 is mounted on one end of the elongate handle 19. By shifting the head section 18 over the elongate handle 19, the light source 190 may be made to project into the reflector 191 in the same manner as an ordinary flashlight, as shown in FIG. 2, or may be located within the elongate sleeve 181 to permit use of the lighting device as a signaling baton, as shown in FIG. 3.
Although the head section 18 is longitudinally shiftable over the elongate handle 19, the head section 18 cannot be maintained at a desired position relative to the elongate handle 19. Thus, the conventional lighting device cannot maintain a desired focusing effect.